Do practice characteristics explain differences in morbidity estimates between electronic health record based general practice registration networks?

BACKGROUND: General practice based registration networks (GPRNs) provide information on population health derived from electronic health records (EHR). Morbidity estimates from different GPRNs reveal considerable, unexplained differences. Previous research showed that population characteristics could not explain this variation. In this study we investigate the influence of practice characteristics on the variation in incidence and prevalence figures between general practices and between GPRNs. METHODS: We analyzed the influence of eight practice characteristics, such as type of practice, percentage female general practitioners, and employment of a practice nurse, on the variation in morbidity estimates of twelve diseases between six Dutch GPRNs. We used multilevel logistic regression analysis and expressed the variation between practices and GPRNs in median odds ratios (MOR). Furthermore, we analyzed the influence of type of EHR software package and province within one large national GPRN. RESULTS: Hardly any practice characteristic showed an effect on morbidity estimates. Adjusting for the practice characteristics did also not alter the variation between practices or between GPRNs, as MORs remained stable. The EHR software package 'Medicom' and the province 'Groningen' showed significant effects on the prevalence figures of several diseases, but this hardly diminished the variation between practices. CONCLUSION: Practice characteristics do not explain the differences in morbidity estimates between GPRNs.

Clinical relevance of diagnosing structural chromosome abnormalities in couples with repeated miscarriage.

BACKGROUND: The annual number of parental karyotypes in cases of repeated miscarriage is increasing gradually in The Netherlands. The efficiency of offering parental karyotyping in couples with repeated miscarriage has not been evaluated before, especially not for the group with miscarriages at advanced maternal age. METHODS: A historical cohort study and nested case-control study were conducted, including couples with at least two miscarriages. Data were retrieved from medical records and telephone interviews. The obstetric follow-up was recorded for > or =2 years after the parental chromosome analysis. Data were analysed to compare ratios of carrier/non-carrier couples in whom maternal age was > or =36 or <36 years at the second, third or fourth and more miscarriage. A projected prevalence of carrier status of a structural chromosome abnormality was calculated by extrapolating the number of included patients to the original level of the total screening population. RESULTS: Forty-one couples with carrier status of a structural chromosome abnormality and 74 couples without carrier status were included. No unbalanced offspring arose after the detection of a structural chromosome abnormality. The risk of being a carrier was not significantly lower (as might be expected) when women were > or =36 years. Ascertainment after two, three, or four and more miscarriages did not change these findings. CONCLUSIONS: Karyotyping of 1324 couples ascertained for repeated miscarriage did not yield an unbalanced fetal chromosome pattern after the ascertainment of parental carrier status. In women with advanced maternal age, the frequency of carrier status was not lower than in younger women.